It is known to use carboxymethylated cellulosic materials in situations where a high degree of exudate absorption is required. For example, WO 93/12275 describes the production of various absorbent products capable of absorbing many times their own weight of water. This causes the carboxymethylated fibers to form a gel. WO 94/16746 and WO 00/01425 describe the use of carboxymethylated Lyocell materials in wound dressings where the advantages of gel formation in preventing adherence and, therefore, reducing wound damage and pain on removal are discussed.
Known wound dressings comprising gel forming fibers are essentially flat, rectangular and fairly small, typically 20 cm×15 cm. The usefulness of such dressings is limited in respect of large-scale wounds such as can occur on the chest or limbs due partly to the contraction of the dressing on gel formation and partly to the difficulty in maintaining close contact with the wound.
For example, wounds to an extensive area such as the chest or limb are presently treated using many overlapping patch type dressings. The contraction on the absorption of exudate is accommodated by overlapping the dressings. This then presents a problem in fixing the dressings and maintaining contact with the wound. Even if the dressings were made in larger sizes the problem of contraction would remain.
However, it would be desirable to bring the advantages of gel forming dressings to such burns by having the dressings available in bandage form. This is not, however, a simple matter. The current gel forming dressings, if presented in a strip form would contract, which, if allowed to occur unchecked, could apply compression to the burn. The patient's natural acute wound response is to cause a burned area to swell. Contraction of the dressing works against this response and is thus undesirable.
In addition, most gel forming dressings are made from non-woven fabrics. Such fabrics have poor integrity in tension. In applying a bandage it is often desirable to apply slight tension in order to obtain conformity between the bandage and the skin. This would not be possible with a bandage made from a non-woven fabric according to existing technology. The bandage when gelled may also not have sufficient integrity to maintain contact with the wound and may be difficult to remove in one piece.
The present invention, therefore, seeks to provide an improved material for use in wound dressings which mitigates the problems associated with patch dressings on extensive wounds.